wood inlay with rock and resin #1: this is my technique

Here’s my disclaimer! Let me start by saying: wear respirator protection throughout this whole process! This is dangerous dusty work, and I claim no responsibly for what you do with this information. This is just an account of what I do.

It took me awhile to figure out the inlay piece, and I’m more than willing to share what I’ve learned.

Ive attached rock crushers and a pic of resin and rock on a scrap to my projects section- im just not up to speed on this HTML stuff yet.

I will highlight the difference that I use for inlay with Stephen Hatcher’s approach. My approach is faster, cruder, guerilla inlay over wider dimensions. It lends itself to more impressionistic inlay, rather than the well controlled approach that Mr. Hatcher so competently uses. It may also be cheaper to do (for its size), because I am not solely using CA glue, but I do use more stone material. (so maybe its not cheaper). I learned ½ of what I know in this area from the following article and the other ½ I’ve learned from trial and error and other web sources. I will use CA glue for smaller areas, thin cracks, etc., following Mr. Thatcher’s general approach.

Crushing the rock:I built the following tool to crush rock for <$20, but I scored a mini jaw crusher and rigged it up to a gear motor. Now I can load material, set the size, and walk away. I would not sell that contraption for any price. Sometimes I just throw things in it just to watch it pulverize!!! I’m sure OSHA would shut me down in a heartbeat, if this wasn’t just a hobby!!

Cost is an issue when using resins and rock, so I try to get it as cheap as possible and only make the top layer expensive rock.

I buy rock bulk online from eBay, greatrough.com, or collect it in the field. You are generally looking for softer material- MOHS hardness 4-5. But I will go higher (up to 6) for cool stuff. You will end up blowing through MUCH more sandpaper the harder the material you sand. The finer you crush it the easier it grinds sands off, and the easier it flows into voids. Mixed colored material generally does not turn out well. Chrysocolla and Malachite are my favorite materials.

The Process:I lay out my design, cut the voids for inlay, or prepare existing voids by cleaning them. You can prespray your surfaces with finish or shellac to minimize the resin staining around the inlay voids. To save $, I will lay a bed of resin in deeper inlays, allowing about ¼ inch for the rock/resin mixture. I then go to my piles of shells, ammonites, cut abalone pieces, and cut stones, and figure out how to lay out these accent pieces. I try to set them flush w/ the wood surface, and I set them with CA glue. I use painters tape to create dams or pockets for vertical surfaces, when laying in the tape, make sure that the surfaces are dry, and rub it down firmly. You can make folds, or even provide shims so the resin can be poured in vertical cracks.

I generally buy Bondo brand epoxy by the gallon, and mix it up with 2x the hardener, so it is sure to go off. In a warm setting, I mix it well, and THEN add colorant or crushed material. I try to go as think as possible, but still have the stuff flow. Think of pancakes crumpled up with syrup. That’s what its like. I will used putty knives, sticks, etc, to push the mixture in. It is a real mess to work with. You need to make sure there is enough rock in your mix so that as it settles, there is rock that sits proud of the wood surface,

In thicker layers Bondo resin is amber colored, but the colors in the crushed material generally overpowers this. I use colorants too at times, sparingly. I will layer two or three material/resin mixes, aiming for pleasing complementing colors and contrasts.

You end up grinding off at least 1/2 of the material you set in resin, as you want the material and resin to mound above the surface of the inlay area. If not, you end up with a cheap look of resin with a few rocks floating in it, rather than tightly packed rock, bound by resin. If possible, I lay in the resin, tape it and set the piece upside down. Then the rock in the resin with pack against the tape.

Once it has set overnight, or longer if it needs it, I grind what looks like an ugly mess with a cup grinder, carefully, and try to get it right to the surface, but I inevitability leave marks in the wood (usually burn marks) that take a lot of sanding to clean up. It is about as messy and dusty at it gets. I wear an OSHA rated mask, and do it outside on a windy day. My neighbors love me. Fortunately we have acreage.

Once ground and sanded to 60, inevitably there are bubbles, etc left in the surface. I either pack them w/ crushed material and bleed in liquid CA glue, or carefully trowel on wood pore filler that I have colorized to match some of the material. Sometimes I have to go over the surface 2-3 times, and I recheck it with each finer sanding coat.

My favored sanding regimen for flat surfaces is:-grind off with a 100 grit grinding cup. 60-100 grit w/ a belt sander, then on to the RO sander and 60, 100, 150.

My favored sanding regimen for curved surfaces is:-grind off with a 100 grit grinding cup. Float the surface using 60-100 grit Resin Fiber Disc disks and a sander/grinder, then on to the RO sander and 60, 100, 150.

I challenge all of you to improve this process, and then teach me/ share with me your improvements!!! I’m always looking for ways to do this better/faster/easier!!!

Andy, thanks so much for sharing your expertise. This is just what I’ve been looking for as I was kind of afraid to jump in and try my hand at inlay with epoxy or CA glue. I feel a whole lot more confident now having read your blog. Thanks again for sharing.

Thanks for the detailed instructions, Andy… I may have to give this a try… if I can find some colored stones in my local. Seems to be mostly sand and clay… Can different colored granites be crushed for this purpose? I don’t know as they are already seemingly a mix of different colored particles!

This post was very informative for me, since I am trying to find the right product for inlaying stone, in a wood table top. I’ll have to look up CA glue….yes I’m very new to this. lol

I looked for shiny River Rocks everywhere, that would be small enough for my project, without having to buy Pea Gravel. Believe it or not, The Dollar Tree had them in two sizes over by the DIY vases and flowers. I was able to pick out some of the smaller, flatter ones in the big bag, and combine them with the smaller ones. Bought 3 bags of each for $1 a piece. Can’t beat the price. You may want to check out what they have. :)